The tech-laden Nasdaq composite index fell 79.05 points, or 2.2%, to 3,578.52, as Facebook's effort to hit a post-IPO record high stumbled. The social media giant's shares fell below $40, dropping $1.70, or 4.1%, to $39.64.

On Monday, the Dow fell 0.4% to close at 14,946.46, dipping below 15,000 for the second straight week. The S&P 500 index slipped 0.4% to close at 1,656.78, more than 50 points off its all-time closing high of 1,709.67 on Aug. 2. The Nasdaq composite declined to 3,657.57.

Markets in the U.S. were rattled after Secretary of State John Kerry said there was "undeniable" evidence of a large-scale chemical weapons attack by the Syrian government against rebellious civilians last week, and suggested the administration was edging closer to a military response.

Concern over a missile strike against Syria as early as this week is pushing oil and gold higher. Stocks are down as money flows to bonds.
Newslook

In global markets, Japan's Nikkei 225 benchmark closed down 93.91 points, or 0.7%, to 13,542.37. Hong Kong's Hang Seng index finished down 130.55 points, or 0.6%, to 21,874.77, and Mumbai's Sensex index plunged 590 points, 3.2%, to end at 17,968.08 as the nation's currency, the rupee, hit a new low off recent comments in the Federal Reserve's policy-making meeting minutes.

In Europe, stocks sold off: UK's FTSE 100 index finished down 51.13 points, or 0.8% to 6,440.97 and Germany's DAX 30 index tumbled 2.3% to close at 8,242.56. France's CAC 40 index ended down 98.40 points, or 2.4%, to 3,968.73.

Gold, which typically rises as world tensions do, jumped $23 an ounce, or $1.6%, to $1,416.

In the U.S. Treasury market, another traditional safe haven, traders pushed prices up and yields down. The bellwether 10-year Treasury note yield fell to 2.72% from 2.81% Monday as its price surged.

Benchmark oil for October delivery jumped 2.8% to about $109 per barrel in electronic trading on the New York Mercantile Exchange.